Bandsaw Blade Repair.......

YYCHM

YYCHM

(Craig)
Premium Member
I spotted a YouTube where a guy repaired a broken bandsaw blade using silver solder. I have 2 broken blades, some SS, Flux, torch, and Map gas so I thought what the hey lets give it a go.

1.JPG

Clamp the blade ends together, apply flux and then silver solder. Probably a little to much SS there.

2.JPG

Grind off and smooth the excess with a Dremel.

3.JPG

Do the same for the other side.

This looked like it was actually going to work until the joint let loose while I was attempting to take a pic if it bent to about drive pulley radius.

Anyone else try or do this successfully? Do you think a spot welder would work for this kind of repair?

Craig
 
Darren

Darren

Ultra Member
Premium Member
oxy acetylene works good, and anneals the weld at the same time, so its not brittle at the weld
 
Janger

Janger

(John)
Administrator
Vendor
I could never get this to work either Craig. Anybody do this successfully? what are we missing?
 
YYCHM

YYCHM

(Craig)
Premium Member
Janger said:
I could never get this to work either Craig. Anybody do this successfully? what are we missing?
Click to expand...

Dunno, I tried twice on the same blade but the silver solder didn't take at all on the second attempt. What about the spot welder idea?
 
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RobinHood

RobinHood

Ultra Member
Premium Member
I think you need to use a lap joint for more surface area. Taper each end by grinding and then try it.

Tom shows how to do it here.
 
Tom Kitta

Tom Kitta

Ultra Member
I am going to TIG weld mine tomorrow. I have a blade welder but never could figure out how to use it. I guess I practice on the old blade that lost half of its teeth.

I hate doing it as the core is welded with like 24 amps and then the ends need like 16 amps - I have a tendency to screw this up.
 
H

historicalarms

Ultra Member
RobinHood said:
I think you need to use a lap joint for more surface area. Taper each end by grinding and then try it.

Tom shows how to do it here.
Click to expand...
Haha when i first read your post i thought "now how is a lap joint going to go through the saw-cut" ....then i watched the video....prime example of "when all else fails, read the directions"
 
C

Chip Maker

Super User
Tom Kitta said:
I am going to TIG weld mine tomorrow. I have a blade welder but never could figure out how to use it. I guess I practice on the old blade that lost half of its teeth.

I hate doing it as the core is welded with like 24 amps and then the ends need like 16 amps - I have a tendency to screw this up.
Click to expand...
Is your blade welder part of the bandsaw like a DoAll type? If so, I can walk you thru it.
 
Tom Kitta

Tom Kitta

Ultra Member
Chip Maker said:
Is your blade welder part of the bandsaw like a DoAll type? If so, I can walk you thru it.
Click to expand...

Yes it is - I have a German version of 16" DoAll - its almost identical copy.

My blade welder says 3/4 max but my blade is 1"

Most of the experiments with it ended with the blade not fully welded or the weld being uber weak.
 
YYCHM

YYCHM

(Craig)
Premium Member
Ok, took a third kick at the can. This time I ground the break square on the bench grinder and tapered (approx. 25 deg) the lap joint as best I could with the belt sander. That left a 1/8" mating surface on each side of the break. This time she survived being mount and two mild steel test cuts. The blade kind of wobbles and weaves and bumps a bit, but I think that's my fault for not using a guide fence to align the blade ends properly. Will give it another go with the other blade and see if it gets any better.

@Janger the solution appears to be the taper lap joint. I just fixed my second blade and it to survived two test cuts as well. This one runs a little better than my first attempt as I was more diligent with the alignment. Good to know this actually works as now I have two backup blades:D

Craig
 
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BMW Rider

BMW Rider

Super User
I've had good luck silver soldering blades for my bandsaw. It uses an odd length blade, so making my own is far easier than trying to find them. I do grind the ends to a bevel to give a larger contact surface. I will quench the joint after soldering, then do the grinding to smooth it out. The last step is to temper it by lightly heating the joint section to a blue colour and allowing to cool so the joint is not so brittle. You do have to be quite careful with the solder joint not to flex it while you do the grinding and until the tempering is done.
 
C

Chip Maker

Super User
Tom Kitta said:
Yes it is - I have a German version of 16" DoAll - its almost identical copy.

My blade welder says 3/4 max but my blade is 1"

Most of the experiments with it ended with the blade not fully welded or the weld being uber weak.
Click to expand...


Ok, It's been a long time since I've welded a blade, but hopefully it's like riding a bike!

First ensure the blade is the right length, sounds basic, but you wouldn't be the first.
Next put one half twist in the blade.
Then sandwich the two ends together pointing in the same direction. So backside of one is aligned with the teeth of the other. Try to ensure they are parallel and then grind the two ends together with the side of the grind wheel. This will give you a matched joint angle regardless of the grind angle, but try your best to keep it 90 degrees to the blade length.
Now clamp the blades on the welder. Make sure they are tight to the back stop and each sticking out the same amount. Do not butt the blades! Try to keep around a 1/32" gap to a maximum of 1/16" gap. You may have to play with this for the optimum weld but once you have it you're laughing.
Weld the blade. The two ends should not overlap and have a similar amount of metal slag squeezed out from each side after the fusion weld.
Remove the blade and bow it slightly to grind the slag on the diameter of the grind wheel. Bow just enough to grind the slag, the weld will be hard and brittle so don't over bend or it will break!
Now you have a shiny ground finish and will able to see the discolouring while annealing.
Put the blade back in the welder with the weld centered then clamp. Jog the anneal switch until the blade turns no more than a dull red. When cooled it should have a blue colour, just like a purchased blade.

Good luck and let me know how it works out.
 
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